Francis III of Brittany

Francis III of Brittany (28 February 1518-10 August 1536) was Duke of Brittany from 20 July 1524 to 10 August 1536, succeeding Claude of Brittany and preceding Henry II of France.

Biography
Francis was born at the Chateau d'Amboise in 1518, the son of Francis I of France and Claude of Brittany, and Francis and his brother Henry spent time at the Spanish court as hostages early in their youths. From 1526 to 1529, the brothers were held hostage by Emperor Charles V as a result of King Francis' defeat at the Battle of Pavia. Francis was the Dauphin (heir apparent) as the King's firstborn son, and he was briefly betrothed to the future Queen Mary I of England. In 1524, he inherited Brittany upon his mother's death, but Brittany was instead ruled by crown officials. Francois died of tuberculosis at his chateau in 1536, with his years spent in a damp, dank cell in Madrid being a major cause of his death; some suspected poison.